Method of producing finely divided metallic products



Patented June 1, 1937 PATE METHOD METALLIC 0F PRODUCING FINELY DIVIDEDPRODUCTS James L. Stevens, Hayden, Ariz.

No Drawing.

Application June 1'7,

Serial No. 27,047

19 Claims.

This invention relates to a method of obtaining metals in a pulverizedor finely divided condition, and more specifically to a method ofobtaining metals in a, finely divided condition such as is suitable foruse as a paint pigment or other purpose for which a fine state ofdivision is required or advantageous. particularly in finely dias apaint useful for the production of copper vided or pulverized conditionfor use pigment.

The invention may also be utilized for the production of alloys ofcopper and other metals such as zinc, and. it will be understood thatreferences to the use or treatment of copper, in the following generalthe appended claims, are intended to include either copper alone orcopper in conjunction with another metal, and that references to theformation of a metallic product comprising copper are intended toinclude either copper alone or an alloy containing copper.

The principal object of the invention is to provide a novel andadvantageous method for producing finely divided metallic productscomprising copper, and particularly for the production of such finelydivided metallic products adapted for use as paint pigments.

A particular object of the invention is to proprocess for the abovepurpose, in which a relatively small expenditure of power is requiredfor reducing the metal to the desired state of division for use.

A further object of the invention is topro-- vide a method for obtainingsuch finely divided metallic products of a high state of purity andfreedom from oxidation.

A further object of the invention is to provide for the production of afinely divided metallic pigment material in pure condition, either aloneor in suspension in a liquid paint vehicle.

A further object of the invention is to provide for the production ofcopper alloys in pulverized or finely divided condition.

Other objects of this invention will be either pointed out hereinafteror will be apparent from the following description of the invention andof certain specific embodiments thereof.

In carrying out the invention, I form an amalgam of copper (or copperand another metal) with mercury, by any suitable amalgamating method;then heat the amalgam to distil off the mercury, leaving a metallicresidue containing the copper (either alone or alloyed with said othermetal) in a spongy or more or less loosely coherent and easilydisintegrated form; and then mechanically break up said metallic residueto reduce it to the desired finely divided condition, as by grinding orpulverizing in any suitable manner.

The physical structure of the metallic residue remaining afterdistillation of the mercury is quite porous or spongy, comprising, athin-walled metallic skeleton penetrated throughout by fine voids orpores, and has relatively little mechanical strength, so that only arelatively light grind ing or pulverizing action is required to reducethis residue to the form of finely divided metallic particles.

The formation of a copper amalgam may be carried out in any suitable orwell-known manner, such as by electrolytic deposition from solutioncontaining a copper salt, using metallic mercury as a cathode, or bychemical reduction and precipitation of the copper from such a solutionin the presence of mercury, or by bringing the copper, preferably individed condition, into contact with mercury in any desired manner.

The proportion of copper introduced into the amalgam may be variedbetween wide limits. As the concentration of amalgamated metal in themercury amalgam increases, the fluidity of the amalgam decreases, and Ihave carried out the process using amalgams of various concentrations,ranging from fiuid to substantially solid amalgams. In general, however,I have found that the best results are obtained by using an amalgam of aplastic, pasty, or semi-fluid consistency, and I therefore prefer to usean amalgem of such a consistency, particularly where the amalgam is aptto be contaminated by impurities, since an amalgam of this concentrationis susceptible to purification by washing, puddling, or working thesame, as hereinafter described. It will be appreciated, however, thatthe amount of metal recovered in an actual embodiment of the process isdependent upon the concentration of the metal in the amalgam, and Itherefore prefer to use as high a concentration as is consistent withother requirements of the process. In the case of copper alone, I havefound that the optimum proportions are about eleven parts of copper toeighty-nine parts of mercury by weight, at which concentration theamalgam may be puddled or worked for removal of impurities, although itis to be understood that the invention is by no means limited to theseproportions.

The amalgam formed as above described if desired, be purified, as bywashing with water or other solvent, or by puddling, working, oragitating the same, either alone or in the presence of water or otherliquid or fluent medium.

the puddling operation, is in some cases advantageous, to assist in theelimination of impurities otherwise worked to break prevent oxidation ofthe amalgam. After preparation of the amalgam, and after desirabletreatment thereof to remove impurities o to produce an amalgam ofuniform consistency, the amalgam is introduced into a retort or othervessel and heated to distil ofi the mercury, the varporized mercurybeing preferably recovered by condensation.

The temperature during the distillation operation should be held belowthe point at which the residual copper might fuse sufiiciently to impairsubsequent reduction of the metallic mass to a pulverized condition. Thedistillation may be carried out under atmospheric pressure, or under anydesired higher or lower pressure. In order to provide completevaporization of the mercury,

5 the mass may be heated to a temperature considerably above the boilingpoint of mercury at the pressure employed, during the later stages ofthe operation.

or damaging The grinding may be in the presence of a product. carriedout either dry or The amalgam may, if deor copper and any otheramalgamable metal or metals adapted to form an alloy with copper, theprocedure is similar to that above described, ex-

precipitation, or by other known means. Alternatively, I may formseparate amalgams of the showed a homogeneous combination of the twometals cury but insulated from the electrolyte by means of a glass tube.

the retort and ground in a pebble mill in the The pulverized metal wasremoved from the mill and separated from the .The product from thisparticular operation appeared to be in the form of crystalline or fiakymasses averaging about .02 mm. in size.

In another laboratory operation, an alloy of zinc and copper wasobtained. In this operation,

the two metals were deposited electrolytically with the mercuryseparately; the copper being deposited from a copper sulphate solutionand the zinc from a zinc sulphate solution. After depositing the desiredamounts of the metals, the amalgam was separated from the aqueoussolution, washed and puddled to remove certain impurities and thensubjected to distillation in a retort for removal of the mercury. Themetallic spongy residue from the retort, having a characteristic colorof dull light yellow brass, was broken up by. grinding in a pebble millin the presence of just sufiicient gasoline to form a metallic paste.After grinding, the pulverized metal was removed from the mill byflushing out with gasoline. The metal was removed from the gasoline bythe procedure described in the foregoing example.

I claim:

1. A method of making a finely divided metallic product which comprisesforming an amalgam containing copper and mercury, distilling the mercuryfrom said amalgam under such conditions as to form a spongy and easilydisintegrated metallic residue comprising said copper, and grinding saidspongy metallic residue to form a finely divided product.

2. A method of making a finely divided metallic product which comprisesforming an amalgam containing copper and mercury by electrolyticdeposition of said copper, distilling the mercury from said amalgamunder such conditions as to form a spongy and easily disintegratedmetallic residue comprising said copper, and grinding said spongymetallic residue to form a finely divided product suitable for use as apaint pigment.

3. A method of making a finely divided metallic product which comprisesforming an amalgam containing copper and mercury, subjecting the amalgamto a puddling operation to remove impurities, distilling the mercuryfrom said amalgam under such conditions as to form a spongy and easilydisintegrated metallic residue comprising said copper, and grinding saidspongy metallic residue to form a finely divided product.

4. A method of making a finely divided metallic product which comprisesforming an amalgam containing copper and mercury, distilling the mercuryfrom said amalgam under such conditions as to form a spongy and easilydisintegrated metallic residue comprising said copper, and grinding saidspongy metallic residue in the presence of an organic liquid to form afinely divided product.

5. In a method of making a finely divided product, the steps whichcomprise: subjecting an amalgam containing copper and mercury todistillation to remove the mercury under such conditions as to form aspongy and easily disintegrated metallic residue; and grinding saidspongy metallic residue in the presence of an organic liquid to form afinely divided product.

6. A method of making a finely divided copper alloy which comprisesforming an amalgam of copper and another metal with mercury, distillingthe mercury from said amalgam under such conditions as to form a spongyand easily disintegrated metallic residue comprising an alloy containingsaid copper and said other metal, and. grinding said spongy metallicresidue to form, a finely divided product.

7. A method of making a finely divided copper alloy which comprises:forming an amalgam of copper and another metal with mercury, distillingthe mercury from said amalgam under suchconditions as to form a spongyand easily disintegrated metallic residue comprising an alloy containingsaid copper and said other metal, and grinding said spongy metallicresidue in the presence of an organic liquid to form a finely, dividedproduct.

8. A method of making a finely divided copper alloy which comprisessuccessively contacting copper and another metal with mercury to form anamalgam containing copper and said other metal, distilling the mercuryfrom said amalgam under such conditions as to form a spongy and easilydisintegrated metallic residue comprising an alloy containing saidcopper and said other metal, and grinding said spongy metallic residueto form a finely divided product.

9. A method of making a finely divided copper alloy which comprisesforming an amalgam of copper with mercury, separately forming an amalgamof another metal with mercury, combining said amalgams to form anamalgam containing copper and said other metal, distilling the mercuryfrom the combined amalgam under such conditions as to form a spongy andeasily disintegrated metallic residue comprising an alloy containingsaid copper and said other metal, and grinding said spongy metallicresidue to form a finely divided product.

10. A method of making a finely divided copper alloy which comprises:forming an amalgam of copper and another or metal by electrolyticdeposition of copper and said other metal in contact with mercury,distilling the mercury from said amalgam under such conditions as toform a spongy and easily disintegrated metallic residue comprising analloy containing said copper and said other meta and grinding saidspongy metallic residue to form a finely divided product.

11. A method of making a finely divided copper alloy which comprisessuccessively electrolytically depositing copper and another metal incontact with mercury to form an amalgam containing copper and said othermetal, distilling the mercury from said amalgam under such conditions asto form a spongy and easily disintegrated metallic residue comprising analloy containing said copper and said other metal, and grinding saidspongy metallic residue to form a finely divided product.

12. A method of making a finely divided metallic product which comprisesforming separate amalgams of copper and another metal with mercury byseparate electrolytic deposition of copper and said other metal incontact with mercury, combining saidamalgams to form an amalgamcontaining copper and said other metal, distilling the mercury from thecombined amalgam under such conditions as to form a spongy and easilydisintegrated metallic residue comprising an alloy containing saidcopper and said other metal, and grinding said spongy metallic residueto form a finely divided product.

13. A method of making a finely divided product which comprises: formingan amalgam containing copper and mercury, distilling the mercury fromsaid amalgam under such conditions oxidation of said metallic residue,to form a finely divided metallic product, and separating said organicliquid from said metallic product.

14. A method of making finely divided copper which comprises forming anamalgam of copper 'with mercury, distilling the mercury from saidamalgam under such conditions as to form a spongy and easilydisintegrated residue of metallic copper, and grinding said spongymetallic copper residue to form a finely divided product.

15. A method of making finely divided copper which compriseselectrolytically depositing copper in contact with mercury to form acopper amalgam, distilling the mercury from said amalgam under suchconditions as to form a spongy and easily disintegrated residue ofmetallic copper, and grinding said spongy metallic copper residue toform a finely divided product.

16. A method of making finely divided copper which comprises forming anamalgam of copper with mercury, distilling the mercury from said amalgamunder such conditions as to form a spongy and easily disintegratedresidue of metallic copper, and grinding said spongy metallic copperresidue in the presence of an organic liquid to form a finely dividedproduct.

17. A method of making a material suitable for use as a metallic pigmentpaint base which comprises forming an amalgam containing copaosascz ,toform a product containing said metallic residue, in finely divided form,suspended in said liquid.

18. A method of making a material suitable for use as a metallic copperpaint base which comprises forming an amalgam of copper with mercury,distilling the mercury from said amalgam under such conditions as toform a spongy and easily disintegrated residue of metallic copper, andgrinding said spongy metallic liquid suitable for use as a paintvehicle, to form a product containing said metallic copper, in finelydivided form, suspended in said liquid.

19. A method of making a material suitable for use as a metallic pigmentpaint base which comprises forming an amalgam of copper and anothermetal with mercury, distilling the mercury from said amalgam under suchconditions as to form a spongy and easily disintegrated metallic residuecomprising an alloy containing copper and said other metal, and grindingsaid spongy metallic residue in the presence of an organic liquidsuitable for use as a paint vehicle, to form a product containing saidmetallic residue, in finely divided form, suspended in said liquid.

JAMES L. STEVENS.

